Guyer signed a minor-league deal with the Giants on Monday, Bob Nightengale of USA Today reports.
Guyer has played 518 games in the big leagues and owns a respectable .250/.339/.388 slash line, good for a 104 wRC+. None of those games came in 2019, however, and the 34-year-old hasn't managed an above-average batting line since 2016, so his chances of making a significant impact in the majors this season appear slim. He hit a modest .244/.367/.366 for Triple-A Charlotte last season.